Cured meat products such as frankfurters containing sodium nitrite curing agents commonly have a pink color which is considered desirable. It would also be desirable if soy protein materials could be combined with meat to provide a very satisfactory combined product. However, when soy materials have heretofore been combined along with meat such as in the production of a soy-extended frankfurter, the result is that the color becomes very pale pink, a color which is not desirable. In order to overcome this disadvantage, it has been proposed to stuff the soy-extended frankfurters into casings which have been dyed a red color. But a disadvantage of such practice is that while the dye from the casing penetrates into the meat surface, the central part of the frankfurter remains pale pink, and when the frankfurter is cut it has a two-tone effect which is undesirable. Further, the dye from the casing leaches into the cooking water which is aesthetically unappealing to the housewife.
The problem is further complicated due to the fact that the sodium nitrite enters into the production of the color and any colorants must function along with the sodium nitrite in this respect.